Retinoic acid is a retinoid sold both for the topical treatment of acne (Retin-A®, Ortho Dermatological, Skillman, N.J.) and for the topical treatment of fine wrinkles, mottled hyperpigmentation, and tactile roughness of facial skin (Renova®, Ortho Dermatological). The compound is formulated into a variety of topical gels, creams, and solutions.
U.S. Pat. No. 5,726,191 recently reported a new class of retinoids. According to the '191 Patent, these compounds can be topically administered in ointments, tinctures, creams, solutions, lotions, sprays, and suspensions. Applicants, however, have found that while members of this class of compounds were very potent in binding to the retinoid receptor, they are chemically unstable in topical formulations.
In fact, applicants tested Compound I, a compound from this class, in a vast array of topical liquid or semisolid pharmaceutical formulations. None of these formulations, however, were capable of sufficiently stabilizing the compound when stored at room temperature (between 20 to 30° C.), thus, inhibiting the ability to market the compound in a topical formulation.
The present invention relates to stabilizing this new class of retinoids in a manner suitable for topical administration.